<div id="editor" contenteditable="true">
	Foo Bar
</div>

<script>
	CKEDITOR.replace( 'editor', {
		toolbar: [ [ 'bold', 'link', 'unlink' ], [ 'btn1', 'btn2', 'btn3' ] ],
		on: {
			pluginsLoaded: function( evt ) {
				evt.editor.ui.addButton( 'btn1', {
					icon: 'Link'
				} );
				// Absolute path.
				evt.editor.ui.addButton( 'btn2', {
					icon: '/apps/ckeditor/tests/_assets/sample_icon.png',
					iconHiDpi: '/apps/ckeditor/tests/_assets/sample_icon.hidpi.png'
				} );
				// Relative path.
				evt.editor.ui.addButton( 'btn3', {
					icon: 'tests/_assets/sample_icon.png',
					iconHiDpi: 'tests/_assets/sample_icon.hidpi.png'
				} );
			}
		}
	} );
</script>
